I really like what you did with the theme, and really like the backgrounds you made they look really nice!
I feel like your use of "special object" was really just pasted on though to be honest. I guess you're smashing the locks with the pickaxe? Doesn't make much sense to me.
Also, there is what (I assume) is a bug where just walking into the locked objects still changes your screen so you can just walk back and forth between locked objects and never become bored.